Duke physicists Jonathan Barés and Robert Behringer and colleagues are using this computerized 3D rendering of beads in a box to serve as a model for soil, sand or snow. Colored lines show the network of forces as the virtual particles are pushed together. Thick red lines connect the particles that are experiencing the brunt of the force.
The sewer gnat is a common nuisance around kitchen and bathroom drains that’s no bigger than a pea. But magnified thousands of times, its compound eyes and bushy antennae resemble a first place winner in a Movember mustache contest.
This Duke “D” is being lit by electromagnetic waves that are normally invisible to the human eye. But they can be seen here thanks to a dielectric metamaterial filter created by Willie Padilla. Metamaterials are synthetic materials composed of individual, engineered cells that together produce properties not found in nature. In this case, that’s the ability to absorb energy in any specific range across the electromagnetic spectrum and convert it into heat.
The “shooting star” patterns in this Mahato Contest Runner-Up aren’t just dazzling to look at – they may also be useful electronics. Graduate students Kristen Collar and Jincheng Li first found these patterns while growing thin films of the semiconductor gallium arsenide. The “stars” start as droplets of liquid gallium on the film surface; as the film grows, they slowly move across the surface, leaving small solid trails -- nanowires -- in their wake.
Sand, snow and other granular materials have a split personality; they can flow through your fingers like a liquid, but if you squeeze them too hard, they “jam,” becoming firm like a solid. Engineers would like to harness this dual nature to create flexible scaffolds for soft robotics or buildings – but first, they must learn to control their behavior. Using transparent beads, researchers in Robert Behringer’s lab investigated how jamming changes when some particles in a material are magnetized.
Duke University researchers believe they have overcome a longstanding hurdle to producing cheaper, more robust ways to print and image across a range of colors extending into the infrared.
As any mantis shrimp will tell you, there are a wide range of "colors" along the electromagnetic spectrum that humans cannot see but which provide a wealth of information. Sensors that extend into the infrared can, for example, identify thousands of plants and minerals, diagnose cancerous melanomas and predict weather patterns, simply by the spectrum of light they reflect.
Like the regular-sized copper wires that power our lamps and computers, miniscule copper nanowires are great at conducting electricity. Duke Professor Benjamin Wiley and his team are investigating how to brew up films thin sheets of copper nanowires that are precisely tailored to work as inexpensive, transparent electrodes in devices like touch screens, light-emitting diodes, and solar cells.
It takes a well-trained eye to spot an irregular heartbeat in the peaks and valleys of an electrocardiogram. The same goes for identifying an extinct ape from a single fossilized tooth, or telling an original van Gogh from a fake.
But in recent years, applied mathematician Ingrid Daubechies has been training computers to churn through ECG tracings, high-resolution scans of fossils, paintings and other complex digital data and work things out automatically.
DURHAM, N.C. – A legacy of acid rain has acidified forest soils throughout the northeastern United States, lowering the growth rate of trees. In an attempt to mitigate this trend, in 1999 scientists added calcium to an experimental forest in New Hampshire; tree growth recovered, but a decade later there was a major increase in the nitrogen content of stream water draining the site.
Tiny spirals of DNA can encode more than just the color of your eyes or the shape of your nose. Using self-assembling DNA wires, Duke engineer Chris Dwyer is building optical computing chips so compact that you could cram 5,000 movies on a single CD-sized disc. The chromophores (red dots) absorb light and transform it into packets of energy called excitons. Then these excitons leap from chromophore to chromophore in a specific pattern.